The embodiment relates to a light emitting device chip, a light emitting device package, and a lighting system.
A light emitting device includes a p-n junction diode having a characteristic of converting electric energy into light energy. The p-n junction diode can be formed by combining group III-V elements of the periodic table. The light emitting device can represent various colors by adjusting the compositional ratio of compound semiconductors.
Meanwhile, in order to realize a white light emitting device package, light emitting devices representing red, green and blue colors, which are three primary colors of light, are combined with each other, the yellow luminescence material (YAG or TAG) is added to the blue light emitting device, or red/green/blue luminescence materials are employed in the UV light emitting device.
Meanwhile, according to the white light emitting device package using the luminescence materials of the related art, a light emitting device chip is positioned on a bottom surface of a reflective cup, an encapsulating material mixed with the luminescence material is filled in the reflective cup, and the white light is formed by mixing the light having a first wavelength generated from the light emitting device chip with the light colliding with the luminescence material and having a wavelength longer than the first wavelength.
However, according to the related art, the luminescence material mixed with the encapsulating material is filled in the reflective cup, so the reflective cup must be provided in the package.
In addition, according to the related art, the light emitting device is adjacent to a luminescence material layer, so heat generated from the light emitting device is transferred to the luminescence material layer, thereby degrading the wavelength conversion efficiency of the luminescence material layer.
Further, according to the related art, particles of the luminescence material may sink during the process, so the concentration of the luminescence material may vary depending on the process time.
In addition, according to the related art, the color temperature variation may occur depending on the viewing angles.